Egalitarian-liberal theories of justice are in principle very demanding, imposing substantial epistemic and justificatory burdens on citizens and requiring substantial changes to social and economic structures. Yet existing democratic institutions show little tendency to manage such burdens well or produce egalitarian outcomes over the long run. I argue that these facts imply a principle for the political realm analogous to John Rawls's famous "difference principle" in the economic and social realms: a political and legal order should be maximally accountable to the representative occupants of the most powerless positions defined by that order, consistent with the equal liberties and fair equality of opportunity principles. This principle may license deviations from the usual institutions of representative democracy in many non-ideal circumstances. I explore the implications of this claim by describing and defending an electoral system where voting power is inversely proportional to income.